Base and socket structure for radio tubes



April 9,f 1935. F. s. MccULLoUGH. 1,995,820

BASE AND SOCKET STRUGTURE FOR RADIO TUBES 'Original Filed Feb. 24, 1925y Emgafm 5ML-big?? VPatented Apr. 9, 1935 SOCKET STRUCTURE FOB RADIOTUBES 4luist: AND

PATENT OFFICE FrderIckvS. McCullough, Edgewood. Pa.

E Original application February 24, 1925, Serial-No.

' 11,083. Divided and this application September 11, 1929, Serial No.391,773

3 Claims. (Cl. 173-328) This is a vdivisional application of myco-pending application Serial Number 11,083, filed February 24, 1925.

This invention pertains to radio tubes, particl ularly receiving tubes,and to a base and socket tion disclosed in that patent in a novel andunique manner.

In my said Letters Patent it is pointed out that considerableimprovement can be made in receiving apparatus by the inclusion of theradio frequency transformer coils of a receiving circuit inside thetube, tothereby reduce the length of interconnecting lead wires andreduce the capacity and impedance of the circuits.

Similar results may be obtained by placing the transformer `in anintegral o r removable base structure for the tube where it is inimmediate proximity to the electrodes of the tube.'

The present invention has for a principal object to provide means at thebase of the tube for coupling a tube having a transformer eitherinsideor at its base into a circuit.

A further object of the invention is to provide a base member, eitherfixed or removably secured to. the tube, inwhich the transformermay behoused.

'I'hese andnther objectsand'advantages are attained by the invention,which may be understood by reference to the accompanying drawing, whichare diagrammatic, and to the details of which the invention is notconfined. In the drawing:

Fig. l represents a section through a tube constructed in accordancewith my invention and having the transformer inside the evacuatedvesseh/the drawing showing one form of my present improvement; v

Pig. 2 is a section through ay tube having the vtransformer in the baseof the tube;

Pig. 3 is a view similar to Fig. 2 of a modiiled base structure; 4 showsadapter: i

Pig. Oshows a socket for use with a tube or the invention applied to atube I adapter embodying the invention;

Fig. 8 is a top view of a portion of'my socketlhowing certain of thedetails in cross section.. Referring to Fig. 1, l designates the usualenvelope having a filament 6, a grid 1, and plate la suitably mounted inthe tube. Within the tube` is a supporting member 8, on which is carriedtwo windings 9 and I0, which may constitute the windings of a radiofrequency transformer. The connections or circuit for the transformermay be arranged according to the requirement of the circuit in which thetube and transformer is included. 'Such circuits are outlined in my saidpatent.

In .the present figure, I have shown the primary 9 in series with theplate through connection I I and the plate contact pin I2 of the tube.The f1 secondary III may have a connection I2a with the filament andhave a terminal connector I3` on the outside of the base Il of the tubethrough `wire I5.v The connector Il may be the usual pin for locking thetube in the socket, as is well known in the art, or it may be a separatepin than the locking pin, or it may be the metal shell of the base when,as it frequently happens, the shell I4 has a metal band forming the sideofits base structure. The tube has the usual grid terniinal pin I6 andlament pins I1.

With this arrangement, it is not necessary to bring a lead wire outthrough the glass envelope, as disclosed in my prior patent and allcircuit connections can be made at the socket. In Fig. 5, I have `showna suitable socket I8 which may be of the standard type with the usualcontacts I9 at the bottom thereof. In addition, a contact strip 29 maybe put in the socket with an exterior terminal connector 2I for contactwith the pin I3 or ll or other terminal for wire I5. The contact strip20 has its end in contactual engagement with the terminal 2l and extendsalong the outer edge ,of the annular wall with its rree end b extendinginto the horizontal portion of the bayonet slot 59. The contact strip 20is under tension so as to normally hold the free end in the slot butwhen a terminal pin such as I3 or 3l is placed in the slot and the tubeis turned; the pin I3 or 3| engages the free end b of the strip 20 andforces it ,outward Vand permits the pin to passv entirely into the slot.The head I of the terminal connector 2| is inset in the wall and makesan additional contact with the 2 i y the primary and l26 the secondary.This transformer is shown as having its primary in series with theplate, as in Fig. 1, though .obviously the transformer might be in thegrid circuit. The

usual two filament connector pins 21 are carried on the base, and `28 isthe usual grid pin and 29 A the plate pin.

on the tube base at au is e contact 3| con-` in all respects to Fig. 2with the exception that,l

instead of a one-piece base of insulating material, as shown in Fig. 2,the base 2S has a metal band 23a and a bottom part 23h of insulatingmaterial.. Such a base is often used in present forms of tubes.' Withthis construction, the wire 32 may be connected to the metal shellinstead y of to a pin on the base, as described in Fig. 2.

'InFig. 4, I have shown a modication permitting present forms of tubesto be used without alteration, and obtain the advantages of thestructures shown in Figs. 1, 2 and 3. In this view, I have shown a. basemember, in which the transformer is contained, adapted to receive thebase of the usual form of tube.

In this gure, 35 designates lthe base of a standard or ordinary tube 3land 36 are the several'contact pins on the bese arranged in the usualmanner. For the purpose of illustration, I have shown these pins in thisfigure, as in the other gures, in line instead of being gnouped as theyordinarily are on a tube. y

These pins are adapted to be projected into suitably arranged holes 38ain a separable base or socket member 21. This base or socket member maybe of the usual socket type or may be in the form of a special socketarranged to t into a standard type of socket and commonly termed anadapter. I have illustrated the special or adapter form 'of socket.y Itmay comprise a suitable body of insulating material 38 in which is thetransformer 39 having windings 40 and 4l, and me y have a metal band l2.On the body are suitable terminals, such as pins 43, for engagement withcontacts in the standard socket,

such as shown in Fig. 5. When the usual tube is plugged into the socketor adapter, the same result is obtained as is obtained, for instance, inthe tube of Fig. 3. The metalband l2 may be the fth. contact point forone of the transformer coils.

In each construction, I have providedvan arrangement wherein thetransformer is, in effect, a a part of the tube. 'I'he length of thelead wires can be minimized and the impedance of radio frequencyampllcation circuits greatly reduced. This is of particular advantage inextremely short wave reception. The invention also enables receivingsets to be 'more easily and compactly assembled.

It will be obvious that various detail changes may be made in theconstruction and design of parts within the contemplation of theinvention and `under the scope of the appended claims.

Having described my invention, what I claim as new and desire to secureby United States Ietters Patent is:

l. In a base socket for audion tubes, an annular wall of insulationforming a recess, a slot in said wallconnecting with the outer free edgethere,- of, a contact strip carried by said annular wall and having aportion extending into said slot to engage a terminal pin on the base ofan audion tube, and a terminal connector on the periphery of saidarmular wall electrically Joined to said contact strip.

2. In'a base socket for audion tubes, an annular wall of insulationforming a recess, a slot in said wall connecting with the outer `freeedge thereof, a contact strip adjacent to said slot and having a portionextending intov said slot to engage a terminal pin on the base of anaudion tube, and a terminal connector on the periphery of said annularwall electrically joined to said contact strip.

3. In a base socket for audion tubes, an annular wall of insulationforming a recess, said annular wall having a bayonet slot thereinadjacent to the free edge thereof, a contact strip adjacent to saidbayonet slot and having a portion extending intosaid slot to engage aterminal 5 pin on the base of an audion tube, and a terminal connectoron the periphery of said annular wall electrically joined to saidcontact strip.`

FREDERICK s. MccUuioUGH.

